Improvement in the manufacture of carbonate of lead



H. HANNENY.

Making White Lead.

N6. 64,763. Patented May 14, 1867.

LA /ff and its contents removed as often as necessary.A

gait-rh tstrs @strut @fitta HENRY HANNEN, or rE1LAnELPH1E,PENNSYLVANIA, AssIeNoE rro s. A; HANNEN AND s. W. GREENE, 'or TEE SAME PLAGE.

Letters Patent No. 64,763, dated Voy 14, 1867.

IMPROVEMENT IN THE MANUEAGTUEE 0E GARBONATE 0F LEAD.

@te rlgrtult afina tu in these iettets atnit mit mating pat nt ,tige same.

TO ALL WHOM IT MAY GONCERN:

Be it known that I, HENRY HANNEN, of Philadelphia, Pennsylvania, have invented an Improvement in the lidanufacture'ot` Carbonate of Lead; and I do hereby declare the followingto be a full, clear, and exact description of the same. I

My invcntionconsists of a mode or process, fully described hereafter, of producing a pure carbonate of lead.

In order to enable others skilled -in the art to practise my invention, I will now proceed to describe a mode oi' carrying the same into effect, reference being had to .the accompanying drawing, which forms a part of this specification, and iniwhich Figure 1 is a vertical section oi' apparatus which may be used for carry-ing my invention into effect.

Figure 2, a rear view partly in section; and

Figure 3, a sectional plan.

A A are the side walls; B the rear wall, and C is the top of a case or chamber in which tits a series of detachable trays, D D, and a drawer, D', the frontsf oi' the trays and drawer forming, when closed, the front of the chamber. The bottoms h of the, traysD D are perforated, or consist of slats, or are otherwise formed so as to retain Hakes or scraps of lead which arc placed in the same, and yet allow of the free passage to and through .the mass of flakes ot' currents of gases. At the rear of the chamber is avverticalA pipe, a, with which communi cate pipes c c, each ofthe latter extending into vthe chamber above one ofthe trays D, and being bent,'as shown iu the drawing, the two parallel portions of each pipe having in the same numerous small or capillaryfperfor tions, for a purpose described hereafter. Each of the pipes c isl closed at the outer end. The pipe a is also closed at its upper end, and in the present instance communicates at the lower end with a `orcepun1p,d,l or its equivalent. Through the top of the chamber passes a tube, e, which communicates with a reservoir containing carbonio acid gas; and above the drawer D is a steam pipe, z', which is bent to a zigzag or othersuitableform, and'which communicates with an adjacent steam boiler. Each of the pipes a c e z' is provided with a'suitable valve or cock, by means ofwhich the passage of tluid through the same may be regulated. In the walls,o i` the chambers are windows or glass-covered openings, through which the attendants may observe thegmaterials being operated on within the chamber, and thus ascertain their condition. The lead which i's'to be convertedl into a carbonate is rst divided into extremely thin iiakes, in a manner which it will be unnecessary ,to describe here,

as it forms'the subjectof aseparate application for Letters Patent. "lheilakes of lead-:areplaced loosely upon the trays D D, and the latter and the drawer D are introduced into the chamber,'as shown in iig. 1, after which steam is passed into the pipe i, so that the contents of the chamber are maintained at a uniform temperature of from 100c to 130. The pump'is now placed in communication with a vessel or reservoir containing water, either pure or slightly acidulated with acetic acid,.and which is impregnated with chlorine, it being'preferable. that the liquor should be of thesame temperature as the contents of the chamber. The piston is now operated so as to force the liquid into the pipesa c, froni'which it is discharged in the form of a fine spray, through the,

perforations inthe pipe, so as to be thrown directly on to the lead in the trays, both above land beneath each pipe, the entire mass of metal being thus thoroughly moistened. After sufficient Water has been discharged on to the metal the action of the `pump is arrested until an oxide has been formed on the Asurface of themetah The pump is then placed in communication withla vessel containing dilute acetic acid, and the latter is then discharged in sprays from the'pipes c and on to the oxide-ted metal, in the same manner as thewaten Thel operation of the pump is again arrested, and as soon as an acetate of lead is formed by the action of the acid on the metalliccxide, the chamber is filled with carbonic a'cid gas, which is introduced through the pipe e, and

which is maintained under a pressure-within the chamber, by' any suitable means, until the acetate of lead isconverted into a carbonate The abovedescribed operations are then repeated as often as may be necessary to convert all the metallic lead into a carbonate. From time to time during-the operation the trays D are agitated, so that theparticles of carbonate may be detached from the lead and fall into a'drawer, D', which is withdrawn In the manufacture of white lead, (incorrectly ltermed carbonate of' lead,) it has heretofore been customary to introduce into a chamber containing coiled strips or sheets of metallic lead, the vapors of water and acetic acid, and carbonio acid gas, by which the lead is rst oxidized, then'converted into an acetate, and then into 1 hydrocarbonate, thc'production of a true carbonate under such circumstances being impossible. Paints made From the hydrocarbonate of lead rbccomediscolored within a greater or less time after their application to the surface of any object, in consequence of the aiinty of the hydrocarbonate for gases in the atmosphere with which it will combine, forming colored compounds.' As, however, carbonate o'flead has no such affinities, paints nadc from the same will not become discolorcd, and it is therefore much superior to the hydrocarbonate, not )nly when. used as a pigment, butv when applied te various other purposes.

I have found, by repeated experiments, that by discharging the water and acid directly on to the metal, nstead of passing them in the form of a vapor into and filling the chamber, not only isv the metal more effectlally moistened, but the carbonio acid gas is permitted to.come into such rapid, direct, and intimate contact vith the metal that it is impossible for, a permanent hydrate to form, and a carbonate of lead is produced. I lave also found that chlorine introduced into the chamber during the transformation of the lead tends to prercnt, when properly applied, the formation ot' a crystalline salt, and that, owing to its bleaching action, a much )urer and whiterproduct is obtained than could otherwise be produced. Care should be taken, however, not to ntroduee an excess of chlorine, the quantity being regulated by thejudgment of the operator. when the carionie acid gas in the chamber is under a pressure it will combine with the oxide of led more quickly and intinately than when ne such pressure is maintained. The oxide of lead, generally termed dross, which forms n the surface of lead when the latter is melted for casting and other.purposes, and which has hitherto been :onsidered an almost refuse material, may be utilized by introducing it into the chamber on the trays D, and reating it in the same manner as the metallic lead` a carbonate as perfect as that formed from the metallic lead icing the result.

Without confining myself` to any particular form of apparatus, or to the precise mode of operation above lcscribed, I claim as my invention, and desire to secure by Letters Patent- 1. The manufacture of carbonate ot' lead by the action, upon metallic lead, or oxide of lead, of water, cetic acid, and carbonio acid gas, when the said fluids are brought in contact with thc lead, substantially as lescribed.'

2. subjecting the lead to the action of carbonio acid gas under a pressure, substantially as and for the urpose set forth. I

8. subjecting the lead, during the process ofits conversioninto a carbonate, to the action of chlorine, for he purpose specified. l i

` In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

i HENRY HANNEN..

Witnesses:

Calamus E. Fosrmi, Jenn WHITE. 

